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Boiler Installation Cost 2024: Full Guide to Boiler Replacement Costs

Boiler installation cost encompasses the combined costs of purchasing and fitting a boiler. Boiler installation costs essentially break down into standalone boiler costs plus the price of labour and material. All together, the total cost of installing a boiler ranges between £2,000-5,000.

Boiler installation cost
Boiler installation costs

It is important to understand the specific factors which comprise boiler fitting costs because the range represents a significant difference of several thousand pounds. In order to accurately estimate the cost of installing a boiler into your specific home, consider the following seven factors.

  • Boiler type: Boiler type affects installation costs for two reasons. First, standalone boiler prices vary by type, with combination boilers typically costing the least and regular boilers being the most expensive. Second, combination boilers are cheaper to install because they don’t require hot water cylinders and water feeder tanks, the way system and regular boilers do.
  • Boiler fuel: Boiler fuel affects both standalone costs as well as labour and materials. Standalone gas and electric boilers are cheaper than LPG and oil boilers of the same heating capacity. Additionally, gas and electric boilers don’t require extra pipework connecting to hot water cylinders or feeder tanks, saving on materials and labour.
  • Boiler size: Boiler-only costs increase with the boiler size (i.e. boiler output in kilowatts).
  • Boiler manufacturer and model: Boilers from premium brands cost more than those from lower-end manufacturers. Every manufacturer also has a range of models for almost every budget.
  • Boiler installer pricing: Some boiler fitters charge more on labour than others. National firms tend to be the more expensive choice for boiler installation than small, regional firms or online installation companies.
  • Site-specific circumstances: Your geographic location, site access, boiler location, and a host of other variables all influence boiler installation costs. Some factors (such as your preferred boiler location) are within your control, whilst others (the part of the country in which you reside) are not.
  • Extras: Any extras you opt to add to your boiler installation increase the total fitting bill. These extras could include boiler filters, a system flush, and other items that enhance your heating system’s performance.

In short, boiler installation costs depend equally on your choices (such as boiler type and accessories) as well as factors beyond your control (such as location). Building awareness of all these factors allows you to select the right fitting service for your needs and budget. Keep reading to learn more about standalone boiler costs, parts and labour, as well as our best savings tips.

How much does a new boiler cost?

The four factors below determine how much a new boiler costs during boiler replacement.

  • Boiler type: The type of boiler you choose greatly impacts your final boiler replacement costs, due to differences in factors like size, piping requirements, and accessories.
  • Boiler fuel: The type of fuel your selected boiler uses affects its installation requirements. Boilers with more popular fuel types also tend to be cheaper due to economies of scale.
  • Boiler size: A larger boiler is more costly to manufacture, driving up boiler-only costs.
  • Boiler brand: Premium boiler brands cost more upfront, but generally provide better durability, performance, and customer support.
boiler installation cost Heatable

Below, you’ll learn more about each of these four variables in-depth.

Does the type of boiler you get determine boiler fitting costs?

Yes, the type of boiler you get determines boiler fitting costs. There are three main boiler types. Each of the three boiler types uses a different mechanism to deliver heating and domestic hot water and comes with a different price tag. The three boiler types are as follows.

  • Combination boilers (also known as “combi boilers”): Combination boilers supply heating and domestic hot water on demand without hot water cylinders or storage tanks. Combi setups are generally the least expensive.
  • System boilers: System boilers heat water and store it in a special cylinder. System boiler setups cost more because the cylinder is an added expense.
  • Regular boilers: Regular boilers get water supply from two storage tanks (one for central heating and one for domestic hot water) and store hot water in a cylinder. These tanks and cylinders increase the regular boiler installation costs.

Combi boilers

Combi boilers are generally the least expensive type of boiler. As a result, combi installation costs are low compared to other boiler types (especially if you’re simply replacing a combi). Combination boilers are especially popular with the British public due to their low fitting cost, small size, and high efficiency. Combi boilers take up little space and don’t require much additional infrastructure, which are important considerations for smaller UK households. Additionally, combination boilers serve hot water on demand, which makes them more efficient than their regular or system boiler peers.

A combination boiler combines both heating and domestic hot water functions within the same appliance thanks to its two heat exchangers. A combi’s primary heat exchanger heats water that circulates throughout the pipes, radiators, and towel rails. Simultaneously, the secondary heat exchanger heats mains water on demand, thus serving hot water to a tap anytime you open it. Since it contains both functions within the same appliance, a combination boiler does not require hot water cylinders or cold water storage tanks to function.

A combi’s compactness makes it cheaper to install, since you needn’t buy or fit any cylinders, cold water storage tanks, or the pipework to connect all these components. That said, combis rely on mains pressure, so the domestic hot water they supply usually comes at a low pressure. If you have a large, thirsty household that runs many taps or showers at once, a combi boiler won’t suffice. Instead, you’ll need a boiler that can provide enough pressure to account for all that simultaneous water use. However, combis work well for smaller households with modest hot water demand.

How to know if I have a combi boiler?

You know you have a combi boiler if your heating system doesn’t have a hot and/or cold water storage tank. In this case, great news: replacing a combi boiler with a new combi boiler typically has the lowest boiler installation cost. However, you’ll pay more to replace a combi with a regular or system boiler because you’ll need to purchase and install equipment for cold and hot water storage.

System boilers

System boilers generally cost more than combis, especially if you’re getting a system boiler to replace another boiler type. The added purchase and installation cost comes from the system boiler’s use of a hot water cylinder. Hot water cylinders keep domestic water hot and raise the temperature of the central heating water. Additionally, these cylinders host coils which central heating water flows through on the way to radiators and towel rails. Unlike combis, system boilers do not serve water on demand. Instead, they heat mains water that gets stored in an insulated cylinder.

A system boiler setup allows for plenty of hot water access, even in larger homes with lots of demand for hot water. Additionally, you needn’t worry about low water pressure due to the system boiler’s hot water cylinder. However, the hot water cylinders take up precious space, which presents a problem for smaller homes. Moreover, these cylinders come at an extra cost and increase the overall boiler installation bill, too.

How to know if I have a system boiler?

You know that you have a system boiler if your home has a hot water cylinder but no cold water tank(s) up in the loft. Having an existing hot water cylinder (along with its pipework) already in your home reduces the price of installing a new system boiler significantly. In fact, this scenario presents the least expensive option for homes fortunate enough to have these critical components already in place.

Replacing an old system boiler with a new one is advantageous if your household uses lots of hot water. Converting a system boiler to combi is an option if you fancy freeing up some space and throwing out the hot water cylinder. But be prepared to spend a few hundred quid more on the associated labour costs.

Regular boilers

Regular boilers (also known as heat-only boilers or conventional boilers) cost a bit more to buy and install (and remove) than system or combi boilers. Regular boilers cost more because of their traditional heating setup, which comprises two cold water feeder tanks, a hot water cylinder, and the boiler itself. Such a setup has lots of moving parts, all of which add to the total installation bill. The cost and physical size of this heating setup makes regular boilers far less popular than their compact combi cousins.

Despite their decreasing popularity, conventional boilers are still relevant. Regular boilers are efficient for large households due to their high capacity hot water cylinders and cold water storage tanks. However, small families should not choose a heat-only boiler since the extra water capacity goes to waste.

How to know if I have a regular boiler?

You know that you have a regular boiler if you have a hot water cylinder and cold water feeder tanks up in the loft. You’ve got the following three options if your regular boiler needs replacement.

  • Swap for a new regular boiler and keep the tanks: This is the least expensive boiler installation option.
  • Replace with a system boiler and discard the cold feeder tanks: This is the more expensive boiler installation option.
  • Convert to a combi and discard the hot and cold water tanks: This is the most expensive boiler installation option.

Does fuel type affect the boiler price?

Yes, fuel type affects the boiler price for two reasons. First, different fuels entails different burner and heat exchange mechanisms, which vary in price. Second, boilers that run on popular and widely available fuels tend to be mass produced, and the economies of scale afford them a lower price tag.

Below is a price comparison for boilers that run on gas, LPG, oil, electricity, and biomass fuel types.

  • Gas boilers: The least expensive boilers are those that run on natural gas and connect to the national gas grid. Gas boilers are by far the most popular in the UK, and their scale of production entails lower prices for the end user.
  • LPG boilers: LPG boilers are slightly pricier, and many gas boiler models come with LPG conversion kits (at an added cost). That said, if you buy an LPG boiler, you’ll need to either purchase or rent an LPG tank to store the liquid fuel, thus adding to your overall boiler installation bill.
  • Oil boilers: Oil boilers cost more than gas or LPG boilers because they have larger, more complex heating mechanisms and because their production is limited. Oil boilers require storage tanks for heating oil, which further add to the cost of boiler installation.
  • Electric boilers: Electric boilers are generally less expensive than oil or LPG boilers, with a similar price point to their gas counterparts. Electric boilers have few moving parts and a simple heating mechanism, and this simplicity contributes to the low price tag.
  • Biomass boilers: Boilers that run on biomass fuels (such as wood pellets, chips, or logs) tend to be the most expensive. They have large, complex heating mechanisms and fuel feeding systems and require a storage container for the fuel.

What kind of fuel does your boiler use?

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Does size affect boiler costs?

Yes, size affects boiler costs: the larger the boiler (the higher its output in kW), the more it costs. The cost differential depends on a range of other factors, including brand, model, and type. However, you can fill out this online calculator from Heatable to get a range of fixed quotes for a number of different boiler sizes.

What size boiler do I need?

There are three options to find out what size boiler you need. Your first option is to call a boiler engineer to come and survey your property. Your second option is to use a boiler size calculator from an online boiler installation company. The calculator factors in key variables to determine the heating output for your home, and gives you prices for the recommended boiler models. We recommend Heatable’s boiler calculator here. The third option is to try sizing the boiler yourself. This final option will likely not produce accurate results, and is suitable for getting a general idea of what size boiler you need. Below is a table that summarises the 3 typical boiler size ranges.

Boiler SizeRadiatorsBathroomsProperty Type
24kW-27kW 10 or less1Smaller properties. Typically, apartments and 2-bedroom terrace houses.
28kW-34kW 10-15 radiators2Medium-sized properties. 2-4 bedrooms.
35kW-42kW 15-20 radiators2Large properties

Does the boiler brand affect replacement boiler costs?

Yes, the brand affects boiler costs: boilers from lower-end brands cost less than models from higher-end brands. That said, most boiler manufacturers offer models for a range of different budgets. Below is a chart with rough gas boiler-only price ranges from UK’s best boiler brands in 2024. (Source: Which?)

Boiler Brand Boiler Price Range
Ariston £1,220-2,950
Vaillant £940-1,770
Viessmann £780-2,480
Worcester Bosch £780-2,050
Alpha £560-2,330
Glow-worm £560-1,660
Baxi £550-1,210
Ideal £510-2,560

What determines labour and materials prices in boiler replacement costs?

The following five variables determine the labour and materials prices in boiler replacement costs.

  • Boiler installers’ pricing: Different boiler installation companies charge you different rates to install a boiler. National companies generally charge more, whilst local and online installers charge less.
  • Boiler types: The costs of fitting a boiler varies depending on the type. A straight, combi-to-combi swap is the cheapest, whilst converting a regular boiler to a combi (or vice versa) costs more.
  • Boiler fuels: Natural gas and electric boilers are the cheapest to install, whilst oil boiler installations cost the most.
  • Site-specific circumstances: The location of your home, the boiler’s location in it, whether or not you need to move the boiler, and the heating system configuration are an installation cost factor.
  • Additional instals: Any extras you get during boiler installation (many of them valuable) drive up the cost of fitting.

Do boiler fitting costs vary between installers?

Yes, boiler fitting costs vary between installers. Boiler replacement costs differ depending on whether you choose a national, local, or online installer. Below is an in-depth explanation of what (and why) different installers charge for boiler fitting.

Boiler installation costs from national installers

National boiler companies charge the most for boiler installations. These nation-wide companies are well-established, trustworthy, and have competent customer support teams. For these reasons, national boiler companies can generally get away with charging more to fit boilers.

British Gas is an example of a national company. British Gas are one of the biggest energy companies in the UK and have a massive presence in the boiler replacement industry for more than 50 years. They promote themselves as the company who “fit more boilers than anyone else in the UK.” But this popularity doesn’t mean that British Gas will give you the best offer. In fact, you should expect to pay a 40-50% “fee” to have a British Gas new boiler installation. Just look at this screenshot of a post on an online forum, made by an individual who has received boiler installation quotes from British Gas.

British gas boiler installation cost

British Gas quotes boiler installation higher than other companies on the market because they invest a lot in marketing. All those adverts with cute animals or the spinning planet you see on TV must be paid by someone. Plus, a large company like British Gas have a lot of overhead costs that they must charge onto the final consumer.

It’s important to remember, however, that even British Gas quotes vary depending on the boiler type, model, size, fuel, and what the installation includes. That said, you can expect to pay much less by using a local or online installer than a large national company.

Boiler installation costs from local installers

Local boiler installers tend to charge less, though their fitting quotes can vary wildly. This price difference stems from many factors, including the local installers’ relationships with boiler manufacturers and reputation among customers. Helpful services like Boilerguide lets you compare up to three local boiler installers in your area in just minutes.

Boiler installation costs from online installers

Online boiler installers charge on the lower end of the scale for boiler installations because their online business model keeps their overhead low. The low overhead creates savings, and the installers are incentivised to pass these savings on to the consumer to stay competitive.

Heatable are a prime example of an online boiler installation company that offers competitive rates for fitting a boiler. We went through Heatable’s quote process as part of our research to see how online companies quote boiler installation. We looked for a combination gas boiler for a 3-bedroom flat, with no additional work required besides the boiler swap. Once we completed the quote process, we got a range of boiler prices (about 10 in total) on our screen. Heatable’s #1 pick, the Worcester Bosch Greenstar 4000, was the perfect new combi boiler for a 3-bedroom flat, at a competitive price to boot. See the screenshot of the sample Heatable quote we received below.

Boiler replacement cost from Heatable

£2,040 is a competitive price for a combi boiler installation, especially when you’re getting a premium Worcester Bosch appliance. Apart from this top pick, Heatable gave us the option for an equivalent boiler in compact form (one that would fit in a kitchen cupboard). That one was in a higher price range, but still a fair deal.

Do different boiler types have different installation costs?

Yes, different boiler types have different installation costs. Below is a summary of labour costs associated with fitting different types of boilers.

  • Combi boiler fitting costs: Combination boilers are the cheapest to fit. Combis don’t require connections to hot water cylinders or cold water feeder tanks, which is why their installation is straightforward and relatively inexpensive.
  • System boiler fitting costs: System boilers cost more to fit than combis because they need to be connected to a hot water cylinder. You’ll pay extra to install the hot water cylinder, too, if you don’t already have one in place.
  • Regular boiler fitting costs: Regular boilers installations are on the higher end of the range because they require connections to hot and cold water tanks. These tanks also require installation (which adds to the overall bill) if you don’t already have them.
  • Costs of converting from one boiler type to another: Converting one boiler type to another costs more than swapping boilers of the same type. Below is how different boiler type conversion scenarios influence installation cost.
    • Regular boiler to system or combi boiler: If you’ve got a regular boiler and want a system or combi boiler, you’ll need to pay for the removal of the hot water cylinder and (for regular-to-system conversions) the water storage tanks. You’ll likewise have to eliminate parts of the existing pipework that comprises your central heating system and reconfigure it to work with the new system or combination boiler.
    • System or combi to regular boiler: Converting a combi or system boiler to a regular boiler entails adding in cold water storage tanks and the pipework to connect the setup. This step adds further costs to the boiler fitting bill.
    • Back boiler to combi boiler: Replacing a back boiler with a combi entails extra costs for removing the back boiler, which is an invasive procedure given back boilers’ location behind a fireplace.

Do boiler installation costs vary based on fuel type?

Yes, boiler installation costs vary based on fuel type. Boilers that run on natural gas are the cheapest to install because the fitter only has to connect them to the gas mains. In contrast, LPG boilers require a fuel tank to be installed and connected to the boiler, and these tasks entail additional labour, resources, and costs. Oil boilers cost more to install than natural gas boilers for two reasons. First, oil boilers have separate fuel tanks the installer must connect to the boiler at an added cost. Second, oil boilers are usually twice as heavy as their gas-fired counterparts, and may require larger crews to fit. The larger the installation crew, the higher the boiler fitting cost.

What site-specific circumstances determine boiler fitting cost?

Below are the site-specific circumstances that determine boiler fitting cost.

  • Geographic location: Labour and material costs vary between different regions of the UK.
  • Boiler relocation: Moving a boiler to a new location adds costs to the boiler replacement.

Certain site-specific circumstances have an impact on boiler installation costs. Keep reading to learn more about the local conditions that drive the cost of fitting a boiler up or down.

Your geographic location

Your geographic location impacts boiler installation costs because labour and material rates vary across different regions of the UK. There’s also a notable cost difference between rural areas, small towns, large cities, and the capital region.

Small cities and towns tend to have the most competitive installation costs. The cost of living in such areas is generally lower, and there’s usually an abundance of heating contractors. That said, rates depend on how competitive the local market is (a factor that may change from one town to another). In contrast, labour costs are higher in a rural area because the contractors have to travel further and spend more time on a single fitting. In large cities, and notably London, the cost to fit a boiler is as high as it gets nationwide. Typical labour rates for boiler installation in central London are as much as 2x that of the price of labour in the North. Elsewhere in the capital, expect to pay at least 25% above the national average to install a boiler.

If you are in London and want to save, our advice is to shop around for the best deals. Another option is to seek a heating engineer based outside London who doesn’t mind travelling in. In any case, consider using an online service like Heatable to quickly compare rates.

Boiler relocation

Relocating a boiler from one place to another in your home involves extra labour that adds to the installation cost. The engineer might need to change pipework and re-drill holes to mount the boiler if your new boiler isn’t the same as your old one. These alterations take time and require materials, which is why they add to the cost of fitting your new boiler.

On the other hand, switching out one boiler for another in the same location is not that complicated a job. The installer has to loosen a few connections, remove the old boiler, and fit the new boiler in its place. In this fortunate scenario, your boiler installer can quickly test the newly installed boiler and sign it off as Gas Safe.

Are there additional tasks that influence boiler replacement costs?

Yes, there are additional tasks that influence boiler replacement costs. Below is an in-depth look at the additional work that may drive up the cost of boiler fitting.

Patching and clean-up

Patching and clean-up happens after any installation, but the scale of this task may differ. A boiler fitter needs to leave your property in the same state they found it. If the install is complex, they might have needed to drill a new core hole for a flue, remove floorboards, or chip away plaster. All of these alterations take time to patch up, and all that additional labour translates into higher boiler fitting costs.

Upgrading the mains gas pipe

Upgrading the mains gas pipe adds costs to the boiler installation charges. You may need to upgrade the mains gas pipe for two reasons. First, older heating systems are usually connected to the mains using a 15mm pipe. However, modern regulations require all new boilers to be connected to the mains with a 22mm pipe. When an installer fits a new boiler, they must make sure the new gas pipe is of the correct size. Second, the pipes may be made of toxic materials, such as lead, and the engineer must replace these. In both scenarios, the pipe replacement adds to the overall cost of installation.

Boiler flue costs

The boiler flue is an essential feature that expels condensation and flue gases, and its installation affects boiler fitting costs for two reasons. First, the replacement is likely to affect the cost of your installation if you must get a new flue. Second, the configuration of the flue can drive the installation cost up or down. Most boilers require a horizontal flue which goes out of the closest wall and just involves a little bit of drilling to install. Installing a horizontal flue is the cheaper option. However, some homes require a vertical flue that has to protrude through your roof. The work to install this is much more extensive because it has to be routed through the roof, and possibly the floor assemblies on the way up. Thus, the cost of installing a vertical flue is higher.

Plume kit

The UK’s Gas Safe regulations may require you to fit a plume kit to your boiler’s flue, a task that comes at an added cost. The regulations state that you must fit a plume kit if the flue is releasing gases in a location where they could harm human health, such as if your flue pipe is too close to a window or your neighbour’s house. Fitting a plume kit is not a complicated job and the kits only cost around £120 or so, but these little extras all add up to inflate the final installation costs.

Modern thermostat

Getting a new boiler presents a good opportunity to upgrade the thermostat, if you don’t mind the extra costs. These days you can opt for the standard wall-mounted thermostat, but a lot of people prefer to invest in an internet-enabled controller. A WiFi-enabled thermostat (such as Hive or Nest) allows you to control their temperatures and hot water from your smartphone. That said, getting one of these gadgets adds £200-500+ to the total boiler installation cost.

Chemical flush

A chemical flush cleanses the heating system before you connect your new appliance to it. Chemical flushes are a costly extra during boiler installation, but they are often invaluable in the long-run. The flushing procedure pushes chemicals through all the pipes in your house which dislodge and flush out any dirt, grime, and sludge that have built up over the years. There are various types of chemical flushes available and prices can vary from around £100 up to several hundred quid.

Magnetic boiler filter

A magnetic boiler filter prevents sludge issues in your boiler and heating system, but fitting it during boiler installation will set you back a bit more. A magnetic filter installed in your pipework attracts small particles of metallic dirt floating around in the system. By trapping these particles, the magnetic stops them from getting into your boiler where they can cause long-term damage.

Often, the cost of installing a magnetic filter is included in the boiler installation quote. The extra will cost you between £100 and £200 if it isn’t.

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Can I get a boiler installed for free?

Yes, you can get a boiler installed for free if you meet the strict eligibility criteria for a government boiler grant. Typically, only pensioners or recipients of specific benefits can get free boilers via the ECO (Energy Company Obligation) scheme. Read our full guide to getting a free boiler to learn more about qualifying.

How can I save money on boiler installation costs?

To save money on boiler installation costs, you have 3 options. First, you can opt for the cheapest possible boiler model. This compromise alone can help you save several hundred pounds up front. However, know that low-end boilers tend to lack reliability, so you may experience issues with performance, breakdowns, and even need a new replacement after a few short years. Your second option is to stick with the same boiler type you have when you get your new one. Boilers of the same type are relatively easy to swap, whereas converting from one type to another costs more. That said, in some cases the energy savings yielded by converting to a different boiler type will offset the extra upfront costs. For example, you will save money over time with a combi boiler, as it heats water on demand if you currently have a regular boiler but your demand for hot water is low. The third (and best) option for saving on boiler installation costs is to shop around and see which boiler fitter offers you the best deal. By being diligent in your research you may find a boiler installation package that’s reasonably priced but includes a premium boiler and all the valuable extras.

How do I find the best boiler installation deal?

To find the best boiler installation deal, follow the three steps below.

  1. Get an online boiler quote: You can get an online boiler installation quote from Heatable in 90 seconds on your screen. The quote will display a range of boiler models suitable for your home, and you’ll get to see which extras are included in the price of the package.
  2. Get quotes from online installers: You should solicit quotes from at least 3 local installers and see what they will charge you to supply and install a boiler model of your choice.
  3. Review the quotes: Spend time reviewing the quotes, line-by-line, to get an understanding of what Heatable and the local fitters offer for their price. You should be able to arrive at a sound decision once you’ve analysed the quotes and determined which one offers best value.
Heatable boiler fitting cost

FAQs about boiler installation cost

Find answers to the most common questions about boiler installation costs below.

When should I install a new boiler?

You should install a new boiler if you’re experiencing any of the following three issues.

  • Your boiler breaks down often and repair bills are getting high: Your appliance is on its last leg if your boiler starts to break down with greater frequency. An increasing frequency of breakdowns points to the end of the boiler components’ service life. Replacing the components is a band-aid fix that simply prolongs the repair visits (and costs) before the boiler finally gives up the ghost. If you find that you have trouble keeping up with repairing your boiler, you should consider installing a new one.
  • Replacement parts are getting hard to find: Trouble sourcing replacement parts for your boiler means that the appliance is severely outdated. Old boilers risk a major breakdown, which may leave you without heating or hot water for a long period. Consider replacing your boiler if your repair technician tells you that they’re struggling to find replacement parts.
  • Your boiler is old and the energy bills are unreasonably high: Replacing an old boiler with a new, efficient model could save you up to £840 per year on your energy bills, according to the Energy Saving Trust. This means that the energy savings could pay for the cost of boiler installation in as little as 3 years.

Which is the best boiler to buy in 2024?

Determining which is the best boiler to buy in 2024 depends on your budget and your home’s needs. Different models may be more suitable depending on how much you’re willing to spend and how much heat and hot water your home requires. That said, going with a premium brand like Worcester or Viessmann is always a good idea, and both of these brands have a range of models for every home size and budget. You can use Heatable’s online questionnaire to see which boiler models are the best in your situation.

How long should a boiler last?

A boiler should last 10-15 years. The boiler lifespan can stretch to two decades if you service the appliance annually and promptly repair any malfunctioning parts. That said, your boiler’s components can develop faults way before 10 years. A good way to see how long a manufacturer expects a given boiler model to function without any faults is to look at the warranty lengths. Boilers that come with longer warranties have their manufacturer’s confidence that the parts will last a while. On the other hand, expect boilers with short warranties to experience component failures after a few short years.

How long does it take to change a boiler?

It takes 1-3 days to change a boiler, with duration hinging on four factors. First, any boiler replacement that entails a conversion from one boiler type to another is bound to take longer. A boiler conversion takes more time because the heating engineer needs to reroute pipework and either set up or dismantle hot and cold water storage tanks. These processes are tedious and add time to the duration of the boiler install. Second, it takes longer to change a boiler if the Gas Safe engineer needs to upgrade the gas mains pipe, as this task can also be quite lengthy. Third, a boiler installation takes longer if the access to the property and the boiler is challenging. For example, if the existing boiler is fitted in a tight space and the street access to your property is narrow, the installer won’t be able to work as fast as they would in a more open space with better access. Fourth, it takes longer to install a boiler if you have to move the new boiler to a new location. Your installer will have to reroute the pipework to the new spot, which can add as much as a day to the boiler fitting process.

Are British Gas boiler installations expensive?

Yes, British Gas boiler installations are expensive compared to those performed by local or online boiler installers. The cost of boiler installation with large national companies like British Gas is generally always higher because these large firms have enormous overheads. These firms’ overheads are inflated thanks to a nation-wide network of mortar-and-brick locations, thousands of staff, and huge marketing budgets. In contrast, small regional boiler fitters have fewer staff, locations, and spend far less on adverts, which gives their prices a competitive edge of firms like British Gas. Online installers (such as Heatable) have even lower overheads because they conduct most of their business online.

Should I oversize my boiler?

No, you shouldn’t oversize your boiler for two reasons. First, an oversized boiler won’t operate efficiently. All the excess heat it generates will fail to dissipate through a smaller radiator network, and the return water will be too hot for the boiler to run on the most efficient, ‘condensing’ mode. By oversizing your boiler, you’ll be wasting heat, and consequently, overpaying for your energy bill. Second, getting a boiler with a higher heating capacity than your home requires means that you’ll overpay for the appliance, as boiler cost goes up with heating output. So, instead of oversizing your boiler, it’s wiser to get a good understanding of what boiler size you need (using a calculator such as this one) before you proceed to buy one.

How much does a new standalone boiler cost?

A standalone boiler costs anywhere from £500 to £6,000, depending on the type, model, capacity, and fuel. New gas combis start at £500 and go as high as £2,000, with £1,000 being the average for a mid-range model. Gas system and regular boilers are just a bit more expensive, typically topping out at £2,500 without installation. Oil and biomass boilers can cost as much as £6,000, excluding fitting or extras.

Can I legally install my own boiler?

No, you cannot legally install your own gas boiler unless you have appropriate certification. Only Gas Safe registered engineers can install gas boilers, while Oil Firing Technical Association (OFTEC) registration is required for anyone installing oil boilers.

Can a plumber install a boiler?

A plumber cannot install a boiler unless they’re Gas Safe or OFTEC registered. Whilst a plumber can service plenty of other components of your heating and hot water system, they can’t legally install a boiler without the appropriate certification, which only heating engineers usually have.

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  1. Sarah says:

    Fantastically comprehensive article here, thanks. I’d certainly argue that getting a boiler from a local company as opposed to one of the big British corporations can be a smart move – after all, all tradespeople must be trained to industry standards and therefore you won’t necessarily get a lower quality of service. Equally, you’ll avoid bureaucracy, and if you’re saved both time and money, there’s no reason not to entrust this expensive purchase into the hands of local plumbers.

    1. Alex Ion says:

      Thank you, Sarah.

  2. John Waldron says:

    Does the 10 year guarantee cover parts & labour, are they installed by local installers who also undertake any repairs. Whoever are responsible for any repairs are they reliable to promptly do them as I.e British Gas would, or are you kept waiting.
    Regards J Waldron.

    1. Alex Ion says:

      Hi John, I think you’ll be dealing with local installers. Maybe this will help? https://www.installeronline.co.uk/33287-2/

  3. Stephen Hall says:

    Is the price the same if the existing boiler is in an internal cupboard with a flue running a few metres through a bedroom cupboard to the outside wall? The existing flue meets the regs, want to check if it can be reused for a different boiler. Thanks, Steve

    1. Alex Ion says:

      I think you will need to use the calculator (see links for BOXT in our article) to find out.

  4. Peter Kemp says:

    Another BOXT advertising webpage claiming to be “independent”.

  5. mark winstone says:

    my boilers 20 years old but its passed 19 services with one to come in november.
    i want to change to a new boiler but British gas dont give out prices. i will go to the websites you suggest to get a price idea.
    another factor is the cost of the service plan. i know i can half it with british gas so i will save there.
    i have an ideal boiler which nhas been great. it has had a few repairs but its still going.
    thanks for your article.

    1. Alex Ion says:

      Hi Mark, glad you liked our article. IDEAL boilers are great. Worcester Bosch are too. I think it may be a price and brand affinity option for you. No?

  6. Leila Jackson says:

    I’ve had a couple of quotes and one for a Potterton Titanic heat only and the other for a Worcester Greenstar 18Ri which I can’t see on your list of boilers. It is currently located in a kitchen cupboard and will be replaced there.
    I have a 5 bedroom, 1 bath and 3 en-suite but have a massive water tank.
    I would need smart thermostats.
    I’m not sure of the answers to some of your questions and wondered if I could talk to someone or whether you do site visits.
    Thank you

    1. Alex Ion says:

      Hi Leila,

      Unfortunately, we don’t do site visits. I think you should check the links in our article, BOXT has great service. We recommend them.

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